The invention relates to a method and a system for establishing a connection from a first communication device, connected to a communication network and having at least one identity, to one or several second communication devices, connected to the communication network and located in a limited location (paging) area, each of them having at least one identity.
In connection with communication systems, especially radiotelephone systems, it is known that the operator of a communication system may change location areas of particular subscribers or subscriber groups by adjusting switches of a routing and controlling panel (dispatcher) connected to a communication exchange. When a calling subscriber then tries to establish a connection with a called subscriber or a group of several called subscribers and if these are located in a predetermined location area, the communication exchange establishes a connection between the calling subscriber and the called subscriber or subscribers.
A typical problem with communication systems containing mobile subscribers is how a calling subscriber may define the location area of a called subscriber or called subscribers, i.e. the area in which the called subscriber or the members of the group of called subscribers are searched for or paged, when a communication message shall be sent to them or a connection shall be established between them and the calling subscriber. It is necessary to define the location area for instance in a situation in which a calling subscriber wishes to establish a connection with a called subscriber or a group of called subscribers only if the called subscriber or subscribers are located in a predetermined area. For example, the calling subscriber wishes to speak with the called subscriber if this is in the neighbourhood, but he does not want to disturb the called subscriber if this is somewhere else, farther away. A definition of the location area is also necessary if the called subscribers with whom the calling subscriber wishes to speak belong to a larger group of called subscribers, but the calling subscriber wishes to speak only with those located in a predetermined location area, i.e. with a part of the group of called subscribers. An expansion of such a case is a situation in which the part of the group of called subscribers with whom the calling subscriber wishes to speak is moving, whereby it is natural that the calling subscriber frequently wishes to define the location area in which the very part of the group of called subscribers is searched for or paged with whom he wishes to speak. A situation of this kind may turn up in connection with radiotelephone systems, for instance, when the part of the group of called subscribers to be searched for moves for some reason; this may be the case, for instance, when all members of the part of the group follow some moving event, such as a moving sporting event. This is typical in radiotelephone systems, in which very many called subscribers use the same group identity. This situation is also possible in a fixed communication system, e.g. a PSTN (Public Switched Telephone Network), in which subscribers may plug in anywhere in the communication network, if only they inform their location to a database, thus enabling the communication network to route communication messages, phone calls, for subscribers to correct network addresses and so to correct subscribers.
A problem with such a prior art method and system for establishing a connection is that a calling subscriber or some other node of the communication network, such as a controller and/or dispatcher of a particular group of subscribers, is not capable of changing the location area in which a called subscriber or called subscribers are searched for or paged. The only possibility is then that the calling subscriber contacts separately a controlling centre existing in connection with the communication exchange. By giving MML (Man-Machine Language) commands to a routing and controlling panel of an operation and maintenance centre of this exchange the operator may then, at the calling subscriber's command, change the location area in which the called subscriber or subscribers are searched for or paged. A procedure of this kind is naturally very cumbersome for the calling subscriber and the operator and consumes resources of the communication network. Likewise, the controller and/or dispatcher of the group of subscribers has then no possibility of changing the location area directly, without any help from the operator of the respective communication system.